I had this at the beginning of my Twitching and I can say that this is 100% caused by anxiety!Everytime I was going for sleep, my whole Body twichted and it felt like my Body has forgotten to breath. So I had to take a deep breath and some adrenaline went trough my vens.....At bad nights this was a never ending Story and it was not possible for me to sleep.

And by the time my anxiety was reduced, this issue was getting slighter until it has gone completely.So I can say that this is 100% related to anxiety.

I am sure it is linked to anxiety and maybe hyperventiliation. Plus, think about it, it is perfectly NORMAL to breathe involuntarily. It is when you start paying attention to every bodily function it doesn't work right. -- yawn, hypersalivate...

Matthew 6:27 Who of you by worrying can add a single hour to his life?